Optimization of a procedure for the selective isolation of some powerful aroma thiols. Development and validation of a quantitative method for their determination in wine.

This paper deals with the isolation properties of four relevant wine mercaptans in two different separation systems and with the subsequent development, optimization and validation of an analytical procedure for their quantitative determination. 4-Methyl-4-mercaptopentanone (4M4MP), 2-furanmethanethiol (FFT), 3-mercaptohexanol (3MH) and 3-mercaptohexyl acetate (AMH) can be quantitatively extracted from 200 ml of wine in a bed packed with 1 g of LiChrolut EN resins. Fatty acids and diverse interfering compounds are removed by rinsing with an aqueous solution with a 40% of methanol and buffered at pH 7.

Relationship between varietal amino acid profile of grapes and wine aromatic composition. Experiments with model solutions and chemometric study.

Synthetic solutions containing amino acids, sugar, water, and yeast nutrients have been fermented by Saccharomyces cerevisiae, and the volatile composition of the fermented media has been analyzed by GC. Eleven amino acid compositions imitating the characteristic amino acid profile of 11 different grape varieties were tested. Significant differences in the levels of some important volatile compounds (ethanol, ethyl acetate, acetic acid, higher alcohols and some of their acetates, methionol, isobutyric acid, ethyl butyrate, and hexanoic and octanoic acids) were found.